kamyu104/LeetCode-Solutions: A 4059-Problem Reference in Python and Modern C++

What kamyu104/LeetCode-Solutions actually is, and who it is for

This repository is a single-maintainer archive of solved LeetCode problems, written in Python and modern C++. The README's progress badge reads 4059 / 4059, and the repository description says the same number, so the claim is that every problem on the site has an answer here. The README also states that new LeetCode questions appear every week and that the author will keep updating for a full summary and better solutions. The last push was on 2026-09-22.

The audience is narrower than the problem count suggests. If you are working through a problem set and want to compare your approach against a second implementation, the repository is directly useful. If you want to understand why a greedy choice is safe, or how a DP recurrence was derived, it will not help you. The README says so itself: because free questions may be taken down, only solutions will be posted now. That sentence explains the repository's shape. It is a code archive with the questions stripped out.

A second detail matters for anyone outside a specific set of languages. The README's index tables link C++ and Python for most entries, and the top level of the repository also contains directories for C#, Golang, Java, Kotlin, MySQL, PHP, Python3, Ruby, Rust, Shell, Swift and TypeScript. The README's own headings list JavaScript, SQL and Pandas sections as well. Coverage across those directories is not described in the README, so treat the non-C++ and non-Python directories as a bonus rather than the product.

How the index, the tags and the complexity columns are organised

The repository is not a flat pile of files. It is an index first. The README opens with a Solutions list pointing at three range files (0001-1000.md, 1001-2000.md, 2001-3000.md) plus the README itself for 3001 to the latest problem. Each range file holds the tables; the README holds the most recent problems plus the algorithm index.

Those tables are the real interface. A row carries the problem number, a link to the problem on leetcode.com, links to the C++ and Python files, a time complexity, a space complexity, a difficulty, a lock marker, and a tag. The complexity values are written in plain notation such as O(logn), O(1) and O(nlogr). The lock marker is a padlock character, and the README states that it means a LeetCode premium subscription is required to read the question. That is a useful signal: a locked problem in this repository gives you working code for a problem statement you cannot read without paying.

The README's algorithm index is the other half of the structure. It lists headings for Bit Manipulation, Array, String, Linked List, Stack, Queue, Binary Heap, Tree, Hash Table, Math, Sort, Two Pointers, Recursion, Binary Search, Binary Search Tree, Breadth-First Search, Depth-First Search, Backtracking, Dynamic Programming, Greedy, Graph, Geometry, Simulation, Constructive Algorithms and Design, plus separate JavaScript, SQL and Pandas sections. Problems appear under a tag, so the same problem can surface in more than one place if it belongs to more than one category.

The source files follow a predictable naming convention: the problem title in lowercase, hyphenated, with a .cpp or .py extension, under a C++ or Python directory. The Bit Manipulation table shows this directly, for example minimum-array-end.cpp and minimum-array-end.py for problem 3133, and count-triplets-with-even-xor-set-bits-i.cpp and count-triplets-with-even-xor-set-bits-i.py for problem 3199. If you know the problem title, you can guess the path without reading the table at all.

Getting the solutions locally and finding one problem

There is no package to install and no build system described in the README. The repository is source files and Markdown tables, so the workflow is a clone and a search. The README does not document a supported compiler version or a Python version, so pin those yourself.

The repository's own URL is the only install step the README implies. Cloning it gives you the range files, the README, and the per-language directories. The README does not print a clone command, so nothing here is copied from a documented quickstart; the path below is the repository address itself.

git clone https://github.com/kamyu104/LeetCode-Solutions.git

To find a specific problem, search the index tables rather than the source tree, because the tables carry the complexity and tag metadata that the files do not. The README's Solutions list gives the file names to search: 0001-1000.md, 1001-2000.md, 2001-3000.md, and README.md for 3001 to the latest problem. Searching for the hyphenated problem title, such as minimum-array-end, finds the table row with the links to the C++ and Python files and the stated complexities. From there you open the file directly. For problem 3133 the C++ file is C++/minimum-array-end.cpp and the Python file is Python/minimum-array-end.py.

Running a solution is not a supported path. The files are written as LeetCode submissions, so they expose the class and method signature the judge expects, not a main function or a test harness. The README does not describe how to execute any file standalone. Expect to paste the body into the LeetCode editor, or to write your own driver around the class. There is a .travis.yml at the top level, which suggests some continuous integration existed at some point, but the README does not explain what it runs.

The explanation gap, and why it decides whether this repository helps you

The central trade-off is coverage against explanation. A repository with 4059 solved problems and no write-ups is a lookup table. The README's only concessional line on this is a hope that you enjoy the journey of learning data structures and algorithms, which is not a substitute for an explanation.

This matters most exactly where the repository is strongest. Take problem 3125, Maximum Number That Makes Result of Bitwise AND Zero, listed as O(1) time and O(1) space. A constant-time solution to that problem is not obvious, and a reader who has not seen the trick will get a correct answer and zero understanding. The same applies to the O(logr) entries in the Bit Manipulation table: the complexity column tells you a bit-level argument exists, and the code shows the operations, but the reasoning that connects them lives nowhere in the repository.

The lock marker compounds this. Problems marked with the padlock require a LeetCode premium subscription to read the statement. The README is explicit about that. So for those rows you have the author's solution and the complexity, and no way to check it against the original question without paying. If your goal is practice, a locked problem you cannot read is not practice.

There is also the question of what a solution is for. Reading a correct solution before you have struggled with a problem tends to produce recognition rather than recall. The repository cannot prevent that, and its structure encourages it: one search, one file, done. The tool is honest about being a solution archive. The reader has to supply the discipline.

How it compares with a written-up solution site

The obvious alternative is a solution site that pairs each problem with an explanation, a walkthrough and often multiple approaches, with discussion underneath. The difference is not quality, it is what you are buying. A written-up site gives you reasoning and a comment thread where wrong approaches get corrected. This repository gives you a large, consistent, single-author codebase with complexity annotations and no discussion at all.

That consistency has value. One author's style across thousands of files means the idioms repeat, and once you have read a dozen of the C++ files you can skim the rest quickly. The index tables also give you something a discussion site usually does not: a clean, searchable complexity column you can filter on. If you want every problem tagged Bit Manipulation that runs in O(1) space, the tables answer that in one pass.

The cost is that there is no second opinion. A discussion site surfaces the approach that is easier to reason about even when it is slower; this repository gives one author's answer, and the README's framing (better solutions, full summary) implies the author revises over time, but there is no changelog or review process described. For a reference you consult after solving a problem, that is fine. For a reference you consult instead of solving it, the lack of debate is a real loss.

Licence, maintenance and what updating costs you

The repository is MIT licensed, and the README carries an MIT badge linking to LICENSE.md. MIT is permissive: it allows reuse, modification and redistribution provided the copyright notice and permission notice are retained. That covers the code. It does not cover the problem statements, which are not in the repository anyway, and it does not cover the LeetCode name or the linked problems. If you plan to republish these solutions in a product, the licence text in LICENSE.md is the document that governs, not the badge. This is a description of the licence, not legal advice.

On maintenance, the evidence is narrow and concrete. The repository is not archived, and the last push was on 2026-09-22. The README describes a weekly update cadence and says new LeetCode questions appear every week. There are no releases, so there is nothing to pin and no versioned artifact to upgrade. Upgrading means pulling master again and accepting whatever changed, which for a solutions repository is usually additive but is not guaranteed to be.

The real upgrade cost is not technical. It is that the repository mirrors a moving target. LeetCode adds problems, and the README notes that free questions may be taken down. A problem can disappear from the site while its solution stays in this repository, or a problem can be added and sit unsolved until the next push. If you are using the index as a checklist, expect the counts to drift from what the site shows. There is a REFERENCE.md at the top level and a CONTRIBUTING.md, neither of which the README explains.

Editorial conclusion

Use kamyu104/LeetCode-Solutions when you want a second implementation of a specific problem, or a C++ version of something you have only seen solved in Python, and you already understand the underlying technique. Do not use it as your primary way to learn algorithms: the README states that only solutions are posted, so there is no reasoning to read, and a solution you cannot reconstruct afterwards has taught you nothing. Before relying on it, open the file for the problem you care about and check that the time and space complexity listed in the index table matches the code you find there. If the two disagree, trust the code.

Frequently asked questions

Official sources

1. Issues
2. kamyu104/LeetCode-Solutions on GitHub
3. License: MIT
4. README